title: Sleep quality and insomnia in nurses with different circadian chronotypes: morningness and eveningness orientation.
abstract: BACKGROUND
  Morningness and eveningness preference (chronotype), an endogenous component of the circadian clock could play a key role in a worker's ability for adjusting to shift work. Morning types are those individuals who prefer going to bed and waking up early, whereas Evening types tend to sleep at later hours and find it difficult to get up in the morning.
  
  
  OBJECTIVE
  The objective of this study was to survey, the relationship between morningness-eveningness type, sleep quality and insomnia in shift worker nurses.
  
  
  METHODS
  The participants comprised 160 nurses working in three different wards in two university hospitals in Iran.
  
  
  METHODS
  Nurses completed the Horne and Ostberg questionnaire to assess the distribution of morningness or eveningness preference, the Pittsburg Sleep Quality Index and Insomnia Severity Index questionnaire to measure self reported sleep quality and insomnia. Demographic information was also collected in order to explore the relationship between circadian rhythms, sleep quality and prevalence of insomnia in shift workers.
  
  
  RESULTS
  The results showed that the prevalence of poor sleep quality was high. More than half of the participants had poor sleep. Evening type nurses had worse sleep quality in our study (P < 0.05). There is not any significant association between the shift type and age of the nurses with their quality of sleep (P > 0.05).
  
  
  CONCLUSIONS
  The results suggested that nurses who had a morning sleep preference had better sleep quality. A survey of chronotype of nurses could be useful, so that individuals may be assigned to different shifts according to their sleep preference.
authors.affiliation: Qazvin University of Medical Sciences, Qazvin, Iran.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Yazdi
authors.affiliation: Department of Occupational Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Khosro
authors.initials: K
authors.lastname: Sadeghniiat-Haghighi
authors.affiliation: Qazvin University of Medical Sciences, Qazvin, Iran.
authors.forename: Ali Reza Haj Seid
authors.initials: AR
authors.lastname: Javadi
authors.affiliation: Qazvin University of Medical Sciences, Qazvin, Iran.
authors.forename: Ghasem
authors.initials: G
authors.lastname: Rikhtegar
mesh_terms: D000328:Adult; D057906:Circadian Clocks / Q000502:physiology*; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D009741:Nursing Staff, Hospital; D015995:Prevalence; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology*; D014940:Work Schedule Tolerance / Q000502:physiology*; D055815:Young Adult
keywords: Chronotype; circadian rhythms; morningness-eveningness; nurse management; sleep disturbance